Abstract: Described herein are stereolithographic methods for preparing 3D objects comprising hollow regions and/or multiple materials. In certain embodiments, the methods comprise applying a blocking composition to fill hollow regions in the 3D printed object. In certain embodiments, an absorbent is applied to dispense material into the 3D printed objects and to remove unwanted resin from the hollow regions. Additionally, in certain embodiments, the modular stereolithographic apparatuses described herein contain an invertible, double vat, which enables users easy access to multiple materials throughout the 3D printing process.

Abstract: Various examples are provided related to hydrogen plasma treatment of hafnium oxide. In one example, a method includes depositing a monolayer of a precursor on a first oxide monolayer; forming a second oxide monolayer by applying an oxygen (O2) plasma to the monolayer of the precursor; and creating oxygen vacancies in the second oxide monolayer by applying a hydrogen (H2) plasma to the second oxide monolayer. In another example, a device includes a hafnium oxide (HfO2) based ferroelectric thin film on a first side of a substrate and an electrode layer disposed on the HfO2 based ferroelectric thin film opposite the substrate. The HfO2 film includes a plurality of oxide monolayers including at least one HfO2 monolayer, each of the plurality of oxide monolayers having oxygen vacancies distributed throughout that oxide monolayer.

Abstract: A nano-mechanical acoustical resonator is designed and fabricated with CMOS compatible techniques to apply to mm-wave RF front-ends and 5G wireless communication systems which have extreme small scale and integrated in 3D sensors and actuators.

Abstract: Various examples are provided related to hydrogen plasma treatment of hafnium oxide. In one example, a method includes depositing a monolayer of a precursor on a first oxide monolayer; forming a second oxide monolayer by applying an oxygen (O2) plasma to the monolayer of the precursor; and creating oxygen vacancies in the second oxide monolayer by applying a hydrogen (H2) plasma to the second oxide monolayer. In another example, a device includes a hafnium oxide (HfO2) based ferroelectric thin film on a first side of a substrate and an electrode layer disposed on the HfO2 based ferroelectric thin film opposite the substrate. The HfO2 film includes a plurality of oxide monolayers including at least one HfO2 monolayer, each of the plurality of oxide monolayers having oxygen vacancies distributed throughout that oxide monolayer.

Abstract: A method and device of polymerization to form 3D objects is provided. The method and device incorporate an inert immiscible liquid between a liquid monomer and a light source such that the liquid monomer is polymerized when exposed to polymerization light from the light source at a liquid monomer-inert immiscible liquid interface. The liquid monomer is polymerized into a solid polymer that forms the 3D object.

Abstract: Provided herein is an improved device and method of manufacturing multi-materials 3D objects. The improved device and method inject liquid monomer through a porous substrate to the desired locations along the substrate. The liquid monomer is polymerized by exposure to light to form a solid polymer. Different liquid monomers can be sequentially injected into through the porous substrate to the desired locations along the substrate for formation of 3D objects formed of different polymers.

Abstract: A nano-mechanical acoustical resonator is designed and fabricated with CMOS compatible techniques to apply to mm-wave RF front-ends and 5G wireless communication systems which have extreme small scale and integrated in 3D sensors and actuators. Thin hafnium zirconium oxide (HZO) films are engineered with atomic layer deposition (ALD) to demonstrate large piezoelectric ferroelectric properties (piezoelectric coefficient e31,HZO?23e31,AlN. Various electrical and optical characterization schemes are also used as test-vehicles to characterize ferroelectric and piezoelectric properties, including isolated 10 nm HZO- and 120 nm AlN-transduction ports. The low-temperature and truly conformal nature of ALD process of HZO offers substantial advantages over conventional magnetronsputtered/MOCVD films, including CMOS-compatibility and sidewall transducer integration.

Abstract: Techniques for forming an electronic device having a ferroelectric film are described. The electronic device comprises a ferroelectric material having one or more crystalline structures. The one or more crystalline structures may comprise hafnium, oxygen, and one or more dopants. The one or more dopants are distributed in the ferroelectric material to form a first layer, a second layer, and a third layer. The second layer is positioned between the first layer and the third layer. Distribution of one or more dopants within the first layer, the second layer, and the third layer may promote a crystalline structure to have an orthorhombic phase.

Abstract: Techniques for forming an electronic device having a ferroelectric film are described. The electronic device comprises a ferroelectric material having one or more crystalline structures. The one or more crystalline structures may comprise hafnium, oxygen, and one or more dopants. The one or more dopants are distributed in the ferroelectric material to form a first layer, a second layer, and a third layer. The second layer is positioned between the first layer and the third layer. Distribution of one or more dopants within the first layer, the second layer, and the third layer may promote a crystalline structure to have an orthorhombic phase.

Abstract: Energy harvesting systems and devices are provided that harvest energy from external asynchronous force impulses using fluidic force transfer of the external force impulses to a plurality of compliant piezoelectric layers that seal a corresponding plurality of inner cavities. Each inner cavity can contain a compressible gas. Direct fluidic force transfer can be accomplished via a compressible or incompressible fluid between an external cover and the compliant piezoelectric layers.

Abstract: A shear-stress sensing system can include a floating element whose displacement can be detected through use of optical measurements. The system can utilize high temperature materials to deliver the optical signal to the structure to be measured, which can also utilize high temperature materials. In one embodiment, an intensity modulation or phase modulation of a reflected signal can be measured to determine the shear stress. In another embodiment, a Moire fringe pattern can be used to determine the shear stress.

Abstract: Methods are provided for enhancing properties, including polarization, of thin-film ferroelectric materials in electronic devices. According to one embodiment, a process for enhancing properties of ferroelectric material in a device having completed wafer processing includes applying mechanical stress to the device, independently controlling the temperature of the device to cycle the temperature from room temperature to at or near the Curie temperature of the ferroelectric material and back to room temperature while the device is applied with the mechanical stress, and then removing the mechanical stress. Certain of the subject methods can be performed as part of a back end of line (BEOL) process, and may be performed during the testing phase at wafer or die level.

Abstract: Energy harvesting systems and devices are provided that harvest energy from external asynchronous force impulses using fluidic force transfer of the external force impulses to a plurality of compliant piezoelectric layers that seal a corresponding plurality of inner cavities. Each inner cavity can contain a compressible gas. Direct fluidic force transfer can be accomplished via a compressible or incompressible fluid between an external cover and the compliant piezoelectric layers.

Abstract: In one embodiment, a neural interface system includes an implantable neural probe having a flexible substrate, electrodes that extend from the substrate that are adapted to contact neural tissue of the brain, a signal processing circuit configured to process neural signals collected with the electrodes, and a wireless transmission circuit configured to wirelessly transmit the processed neural signals, and a backend computing device configured to wirelessly receive the processed neural signals, to process the received signals to reconstruct the collected neural signals, and to analyze the collected neural signals.

Abstract: Methods are provided for enhancing properties, including polarization, of thin-film ferroelectric materials in electronic devices. According to one embodiment, a process for enhancing properties of ferroelectric material in a device having completed wafer processing includes applying mechanical stress to the device, independently controlling the temperature of the device to cycle the temperature from room temperature to at or near the Curie temperature of the ferroelectric material and back to room temperature while the device is applied with the mechanical stress, and then removing the mechanical stress. Certain of the subject methods can be performed as part of a back end of line (BEOL) process, and may be performed during the testing phase at wafer or die level.

Abstract: Embodiments of a vibrational energy harvester are provided. A vibrational energy harvester can include a translator layer sandwiched between two stator layers. The translator layer can include a plate having an array of magnets and two or more piezoelectric patches coupled to a tether beam attached to the plate. The stator layers can have a printed circuit board with multilayer electrical windings situated in a housing. In operation, vibration of the housing can result in bending of the piezoelectric patches coupled to the tether beam. This bending simultaneously results in a relative displacement of the translator, which causes a voltage potential in the piezoelectric patches, and a relative velocity between the translator and the stators, which induces a voltage potential in the stator coils. These voltage potentials generate an AC power, which can be converted to DC power through a rectification circuit incorporating passive and active conversion.

Abstract: Silicon, silicon-germanium alloy, and germanium nanowire optoelectronic devices and methods for fabricating the same are provided. According to one embodiment, a P-I-N device is provided that includes a parallel array of intrinsic silicon, silicon-germanium or germanium nanowires located between a p+ contact and an n+ contact. In certain embodiments, the intrinsic silicon and germanium nanowires can be fabricated with diameters of less than 4.9 nm and 19 nm, respectively. In a further embodiment, vertically stacked silicon, silicon-germanium and germanium nanowires can be formed.

Abstract: A method of fabricating a MEMS flexible substrate neural probe is provided. The method can include applying an insulation layer on a substrate, and depositing a plurality of metal traces on the insulation layer and electroplating each of the plurality of traces. The method also can include encapsulating the insulation layer and metal traces deposited thereon with an insulation layer. Additionally the method can include etching the insulation layer to form a plurality bond pad sites and probes to form a flexible ribbon cable having a plurality of bond pad sites disposed on a surface of the flexible cable and a plurality of neural probes extending from the flexible cable. The method further can include separating the substrate from the insulation layer and depositing insulation on each of the neural probes, each probe comprising insulated portion and exposed metallic tip.

Abstract: Embodiments of a vibrational energy harvester are provided. A vibrational energy harvester can include a translator layer sandwiched between two stator layers. The translator layer can include a plate having an array of magnets and two or more piezoelectric patches coupled to a tether beam attached to the plate. The stator layers can have a printed circuit board with multilayer electrical windings situated in a housing. In operation, vibration of the housing can result in bending of the piezoelectric patches coupled to the tether beam. This bending simultaneously results in a relative displacement of the translator, which causes a voltage potential in the piezoelectric patches, and a relative velocity between the translator and the stators, which induces a voltage potential in the stator coils. These voltage potentials generate an AC power, which can be converted to DC power through a rectification circuit incorporating passive and active conversion.

Abstract: A shear-stress sensing system can include a floating element whose displacement can be detected through use of optical measurements. The system can utilize high temperature materials to deliver the optical signal to the structure to be measured, which can also utilize high temperature materials. In one embodiment, an intensity modulation or phase modulation of a reflected signal can be measured to determine the shear stress. In another embodiment, a Moire fringe pattern can be used to determine the shear stress.